Author Correction: Thermogenesis-triggered seed dispersal in dwarf mistletoe.

This corrects the article DOI: 10.1038/ncomms7262.

Thermogenesis-triggered seed dispersal in dwarf mistletoe.

Lodgepole pine dwarf mistletoe (DM), Arceuthobium americanum, is a parasitic flowering plant and forest pathogen in North America. Seed dispersal in DM occurs by explosive discharge. Notably, slight warming of ripe DM fruit in the laboratory can trigger explosions. Previously, we showed that alternative oxidase, a protein involved in endogenous heat production (thermogenesis) in plants, is present in DM fruit. These observations have led us to investigate if thermogenesis induces discharge. Here, infrared thermographs reveal that ripe DM fruits display an anomalous increase in surface temperature by an average of 2.1±0.8 °C over an average time of 103±29 s (n=9, 95% confidence interval) before dehiscence. Furthermore, both non-isothermal and isothermal modulated differential scanning calorimetry consistently show an exothermic event (~1 J g(-1)) in the non-reversible heat flow just prior to discharge. These results support thermogenesis-triggered seed discharge, never before observed in any plant.

Isolation and characterization of lignins extracted from flax shives using pressurized aqueous ethanol.

High-molecular weight lignins (HML) and low-molecular weight lignins (LML) were extracted from flax shives using pressurized 30% aqueous ethanol, and isolated by precipitation and ultrafiltration. The isolated lignin samples and two commercial lignins were assayed for monolignol content and functional groups, solubility assays, thermal analysis using differential scanning calorimetry (DSC), size exclusion chromatography (SEC), and Fourier transform infrared spectroscopy (FT-IR). The highest yield of HML was 13.5 g/100 g of flax shives, and this was about six times higher than the LML yield. SEC of lignin samples revealed that the molecular weights of HML and LML are about 30,000 and 8749 Da, respectively. The DSC results of HML show that this lignin has a glass transition temperature near 160 degrees C. HML contains fewer carboxyl groups and more phenolic hydroxyl groups than LML. The higher molecular weight and higher thermal stability of HML makes it an excellent candidate for industrial applications.

Influence of added bean flour (Phaseolus vulgaris L.) on some physical and nutritional properties of wheat flour tortillas.

Composite flours containing 15%, 25%, or 35% of small red, black, pinto, or navy bean flours (BF) and wheat were made into tortillas. Dough rheology, firmness, cohesiveness, rollability, and some physical properties of tortillas were negatively affected as BF concentration increased regardless of bean cultivar. Nutritionally, all bean tortillas had significantly higher levels of crude protein, total phenols, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS(+)) in vitro antioxidant activity (AA) and antinutritional compounds such as phytic acid (PA) and trypsin inhibitors (TI) than the wheat control. Tortillas to which 35% of small red, pinto and black BF was added had the highest levels of phenols, which were significantly correlated with both DPPH (r=0.99) and ABTS(+) (r=0.99) AA. Compared to raw flours, PA and TI were reduced from 37.37% to 43.78% and from 50% to 66%, respectively, in the tortillas. Overall analysis indicated that tortillas with acceptable texture and improved nutritional profile were produced at 25% substitution.

Comparison of ultrasonic velocities in dispersive and nondispersive food materials.

Ultrasonic techniques are increasingly being used to evaluate the properties of food materials. Interpretation of the structure and dynamics on the basis of measured ultrasonic parameters requires rigorous definition of ultrasonic parameters such as velocity, especially since many food materials can display considerable dispersive behavior (changes in velocity with frequency). Agar gel (2% w/v) and agar gel (2% w/v) with a regular array of bubbles (8% volume fraction) were chosen as nondispersive and dispersive materials, respectively. Frequency and time domain techniques were used to analyze velocities. Signal, phase, and group velocities were identical in the agar gel and were indistinguishable from those of water (1500 m s(-1)), indicating the predominant effect of the bulk modulus of the water they contain on the longitudinal modulus of the gel. In contrast, the inclusion of the bubbles in the agar gel led to strongly dispersive behavior, with group velocities varying by 1000 m s(-1) above and below the 1500 m s(-1) of the agar gel without bubbles, depending on frequency. The addition of bubbles also led to strong attenuation in the agar gel with a peak occurring at a frequency associated with a band gap arising from destructive interference of sound waves. The results show that care must be taken when comparing ultrasonic parameters derived from experiments on food materials performed at different frequencies or with different ultrasonic techniques.